Conspectus of the pharmacopoeias of the London, Edinburgh, and Dublin Colleges of Physicians ... / [Anthony Todd Thomson].

  • Thomson, Anthony Todd, 1778-1849.
Date:
1830
Catalogue details

Licence: Public Domain Mark

Credit: Conspectus of the pharmacopoeias of the London, Edinburgh, and Dublin Colleges of Physicians ... / [Anthony Todd Thomson]. Source: Wellcome Collection.

    20/238
    hydrogen, carbon, sulphur, and phosphorus; and, when united with oxygen, for acids, alkalies, and the earths. None of tlie metals, except fbi, arc employed in the metallic form as remedies in the practice of medicine; but for pharmaceutical pur- poses it is of iin])ortance to obtain them in as pure a state as possible. Mutallic Salts are either simple combinations of the metals with oxygen, or combinations of their oxyds with acids. Metals combine with various portions of oxygen, which are denoted and expressed by the colour of the oxyds, as oryd of marcuryt red oxyd of mcrcitryi S^c. Oxyds have not the lustre, opacity, te- nacity, nor gravity of the metals; are uninflammable, generally in- sipid, nearly insoluble in water, and have an earthy appearance. They require to be kept in stopped bottles, as some of them are reduced by hydrogen, which is more or less constantly floating in the atmosphere. The metallic saltn, which, properly speaking, are oxyds combined with the acids, are of a saline nature, generally soluble in water, and rr)'staUi/.able. 'J'hey arc named from the acid, and the metal with the oxyd of whicli it is combined, as sulphate of iron, nitrate of silver, muriate of mercury, i^'f. The active properties of metallic salts vary much, according to the degree of previous oxydizement of the metals they contain : thus the same acid, xmited with an imiicr- fect oxyd, will form an insipid, insoluble compound, wliile, with a more perfect oxyd, the compound will be aciid, and soluble in water. In pharmaceutical language, although not strictly correct, the latter salt is distingui.shed by tlie syllable oxy—as oxymuriate of mercury, i)r corrosive sublimate, to distinguish it from submuriate of mercury, or calomel. Metallic salts are not always perfect neutrals When the oxyd is in excess, the syllable sub is added to the name of the salt, ^subnitras bismuthi, subcarboyias jdumhi, Some of these salts, also, are oxyds united with sulphur, sulphuretted hydrogen, phosphate of lime, carbonate of lime, and carbonate of ammonia, and receive appellations in the Pharmacopceias, correspondent to their supposed comj>osition. Many of the metallic salts efliorcsce, and attract oxygen from the atinosi>hcre; others are altered in their properties by moisture, and some of them are decomiiosed by the action of light; hence, perhaps, it ougltt to be a general rule to keep all of them in well-stop])cd bottles made of green glass, or otherwise rendered opaque. In forming those which are soluble into lotions, distilled water should be used; and in mixtures, attention should be paid not to unito them with incompatible substances. PREPARATIONS OF SULPHUR. The combinations of sulphur with the alkalies and the earths arc iiamc<l sulphurcts, and require to be carefully preserved from the almo.sphere, as they attract moisture from it, deliquesce, and arc de- composed. The oxygen of the water acidifies part of the sulphur,